A handful of YouTube channels are dedicated to crushing objects with a hydraulic press. Among the items that have been spectacularly squished against their will in the name of viral entertainment have been a tenderizing mallet, a can of Silly String, a Rubik's Cube, a hockey puck, a couple of bullets and — you guessed it — a diamond.

Although diamonds are the hardest substance known to man, they can be fractured with a blunt force. So when pitted against the 10,000 psi power of a hydraulic press, one would expect the lovely faceted diamond to be turned into a pile of diamond dust.

Last May, the Hydraulic Press Channel put a round 1.2-carat lab-grown diamond to the test. In the video that has been viewed more than 10 million times, we see the press descending slowly on the stone.

The press moves steadily and then seems to meet with just a bit of resistance. In the next instant, the diamond shatters like a piece of glass being bashed by a hammer.

The hardest substance on earth, in this case, was no match for the press.

But then in June, rival YouTube channel Hydraulic Press VS promoted a similar showdown, and the results were startling different.

For its face-off, Hydraulic Press VS used a .25-carat, F-color, SI1-clarity, natural diamond and placed it under the crusher with the pavilion (pointy side) facing down. Unbelievably, the diamond defeats the press as it gets embedded into the steel below — without a scratch. The testers seem to be amazed by the outcome.

When Hydraulic Press VS repeated the challenge with a larger stone placed with the pavilion pointing up, the stone seems to explode under the massive pressure. This video has been viewed more than 11 million times.

It's important to clarify that there is a big difference between hardness and strength. Hardness is a surface property. A diamond earns the top-of-the-line 10 rating on the Mohs hardness scale because no material except for a diamond can scratch it. Sapphires and rubies, by comparison, are rated 9, topaz is rated 8 and quartz is rated 7. Each of these relatively hard materials can be easily fractured with a hammer blow.

Because of a diamond's hardness rating, the material is often used to enhance cutting devices, such as drills and saw blades.

Carbon fiber, on the other hand, is extremely strong but can be easily cut with a standard steel drill bit or even a pocketknife.

Check out the videos below. The first is from the Hydraulic Press Channel and the second is from Hydraulic Press VS.